1. Field of the Invention
The present invention relates generally to signal reception and amplification and more particularly to optimum reception of scattered underwater sound.
2. Description of Prior Art
In the field of underwater sound transmission, the "building and fading" of acoustic signals in the sea has been observed for decades. This phenomenon has been variously attributed to time-varying surface and/or bottom interference, internal waves, and thermal gradients. Regardless of the source, the fading is especially troublesome in underwater communications and in the detection of undersea objects.
As a result, current practice is to eliminate, as much as possible, all but the direct path relatively stable signal that enters an underwater receiver such as a hydrophone. All of the sound received from a source is thus not utilized and results in a loss of efficiency in detecting sound.